Nitride semiconductors have been studied in the fields of optical and high-output electron device development because of their high thermal stability and wide bandgap. Currently, researches for a nitride semiconductor light emitting device are focused on light emitting efficiency improvement.
In order to realize a highly-efficient light emitting device, two methods are required in an aspect of a semiconductor thin film. One method is to increase light coupling probability of electrons and holes injected in a light emitting layer in order to improve internal quantum efficiency. The other method is to increase light extraction efficiency in order to allow light formed in a light emitting layer to escape from a thin layer effectively.
In order to improve internal quantum efficiency, a technique for growing a high-quality thin layer and a technique for optimizing a thin layer stacked structure to maximize quantum efficiency are required. In order to increase light extraction efficiency, various researches for controlling geometrical formation of a light emitting device are in progress.